An Ultra-Wideband High-Linearity CMOS Mixer With New Wideband Active Baluns

摘要

A 2–11-GHz high linearity CMOS down-conversion mixer with wideband active baluns using 0.18-$mu{hbox{m}}$ CMOS technology is demonstrated in this paper. The mixer employs a folded cascode Gilbert cell topology and on-chip broadband active baluns. The folded cascode approach is adopted to increase the output swing, and the linearity is enhanced by a harmonic distortion canceling technique derived from the harmonic balance analysis. The proposed configuration shows the highest ${rm IIP}_{3}$ and ${rm IP}_{1~{rm dB}}$, and exhibits more compact size than most published studies. A broadband active balun is used to generate wideband differential signals, together with the derivation of a closed-form expression for the phase imbalance. This single-ended wideband mixer has the conversion gain of ${{hbox{6.9}}}{ pm {hbox{1.5}}}~{hbox{dB}}$, input 1-dB compression point $({rm IP}_{1~{rm dB}})$ of ${- {hbox{3.5}}}~{hbox{dBm}}$, single-sideband noise figure of 15.5 dB, and third-order input intercept point $({rm IIP}_{3})$ of 6.5 dBm under the power consumption of 25.7 mW from a 1.8-V power supply. The chip area is 0.85$,times,$0.57 ${hbox{mm}}^{2}$.